The present invention is directed towards an electronic input/display system, and more particularly towards those electronic input/display systems including touch sensitive screens which allow for the manual input of data via the system's display device.
Recently, computer systems have become more compact, smaller in size, and lighter in weight. More and more functions are being integrated into smaller and smaller devices, due to the advent of smaller and more powerful microprocessors. For example, today it is quite common to find personal organizers which include editors, spreadsheets, or cellular phone capabilities.
Most portable devices on the market to-date are foldable with separate keyboards and displays. The keyboards are normally on one half of the unit (i.e., the base) and the display on the other (i.e., the lid). Attempts have been made to reduce the overall size of these units. Some manufacturers have reduced the size of portable devices by reducing the size of the unit's keyboard. Typically in those systems, the same physical key corresponds to multiple letters, e.g., A, B, and C. The letters are either toggled with each key stroke, e.g., requiring 3 key strokes for the letter C, or the unit uses a dictionary to guess the words when the space bar is pressed, showing alternatives when more than one word meets the sequence of key strokes.
Units also exist without a separate keyboard, instead being equipped with a touch screen that both displays, and allows the user to enter, information. A virtual keypad displayed on the screen is often the input mechanism for these units. The user can press a virtual key either using his/her finger tops or some special pointing device, e.g., a stylus. The touch is sensed by the unit, and the selected character is a result of the location of the touch. U.S. Pat. No. 5,457,454 to Sugano discloses such a unit wherein keys are selected by means of a write-pen. Such a system limits the speed at which data can be input.
Moreover, in portable devices with smaller display screens, a virtual alphanumeric keypad tends to cover most of the screen allowing little, if any, information to be shown simultaneously with data input. This makes tasks, such as text editing, difficult, since most users like to frequently and instantly review what they have typed.
Therefore, a need exists for small portable devices that can simultaneously present large amounts of information and allow quick and easy entering of information using a touch sensitive display.